On model checking data-independent systems with arrays without reset

A system is data-independent with respect to a data type X iff the operations it can perform on values of type X are restricted to just equality testing. The system may also store, input and output values of type X. We study model checking of systems which are data-independent with respect to two distinct type variables X and Y, and may in addition use arrays with indices from X and values from Y . Our main interest is the following parameterised model-checking problem: whether a given program satisfies a given temporal-logic formula for all non-empty nite instances of X and Y . Initially, we consider instead the abstraction where X and Y are infinite and where partial functions with finite domains are used to model arrays. Using a translation to data-independent systems without arrays, we show that the u-calculus model-checking problem is decidable for these systems. From this result, we can deduce properties of all systems with finite instances of X and Y . We show that there is a procedure for the above parameterised model-checking problem of the universal fragment of the u-calculus, such that it always terminates but may give false negatives. We also deduce that the parameterised model-checking problem of the universal disjunction-free fragment of the u-calculus is decidable. Practical motivations for model checking data-independent systems with arrays include verification of memory and cache systems, where X is the type of memory addresses, and Y the type of storable values. As an example we verify a fault-tolerant memory interface over a set of unreliable memories.Comment: Appeared in Theory and Practice of Logic Programming, vol. 4, no. 5&6, 200

A Branching Time Model of CSP

I present a branching time model of CSP that is finer than all other models of CSP proposed thus far. It is obtained by taking a semantic equivalence from the linear time - branching time spectrum, namely divergence-preserving coupled similarity, and showing that it is a congruence for the operators of CSP. This equivalence belongs to the bisimulation family of semantic equivalences, in the sense that on transition systems without internal actions it coincides with strong bisimilarity. Nevertheless, enough of the equational laws of CSP remain to obtain a complete axiomatisation for closed, recursion-free terms.Comment: Dedicated to Bill Roscoe, on the occasion of his 60th birthda

Cholecystitis: Etiology, Diagnosis and Treatment

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Isolated proteinuria in asymptomatic patients

Presentation of the Forum is made possible by grants from Smith Kline & French Laboratories, Hoechst-Roussel Pharmaceuticals Inc., CIBA Pharmaceutical Company, GEIGY Pharmaceuticals, and Boehringer Ingelheim Ltd

Effects of magnification and visual accommodation on aimpoint estimation in simulated landings with real and virtual image displays

Twenty professional pilots observed a computer-generated airport scene during simulated autopilot-coupled night landing approaches and at two points (20 sec and 10 sec before touchdown) judged whether the airplane would undershoot or overshoot the aimpoint. Visual accommodation was continuously measured using an automatic infrared optometer. Experimental variables included approach slope angle, display magnification, visual focus demand (using ophthalmic lenses), and presentation of the display as either a real (direct view) or a virtual (collimated) image. Aimpoint judgments shifted predictably with actual approach slope and display magnification. Both pilot judgments and measured accommodation interacted with focus demand with real-image displays but not with virtual-image displays. With either type of display, measured accommodation lagged far behind focus demand and was reliably less responsive to the virtual images. Pilot judgments shifted dramatically from an overwhelming perceived-overshoot bias 20 sec before touchdown to a reliable undershoot bias 10 sec later

Influência do uso de areia lavada na taxa de respiração de um latossolo vermelho distroférrico argiloso incubado com agregados íntegros e triturados

bitstream/item/66211/1/32008.pdfFERTBIO

Ubiquitous energy storage

This paper presents a vision of a future power system with "ubiquitous energy storage", where storage would be utilized at all levels of the electricity system. The growing requirement for storage is reviewed, driven by the expansion of distributed generation. The capabilities and existing applications of various storage technologies are presented, providing a useful review of the state of the art. Energy storage will have to be integrated with the power system and there are various ways in which this may be achieved. Some of these options are discussed, as are commercial and regulatory issues. In two case studies, the costs and benefits of some storage options are assessed. It is concluded that electrical storage is not cost effective but that thermal storage offers attractive opportunities

Changes in lindane residue.

The bulletin reports on Department of Horticulture Research Project 197, 'Elimination of chemical residues'--P. [2].Digitized 2007 AES.Includes bibliographical references (page 16)

Multi stakeholder Perspectives of the Determinants of Family Fundamental Movement Skills Practice: A Qualitative Systematic Review

Background: Childhood obesity is a significant public health crisis that is exposing children to associated morbidities and premature mortality. However, parents can positively influence physical activity trajectories and improve health outcomes by nurturing fundamental movement skills (FMS) in children. This is the first study to explore the determinants of family FMS practice via a systematic synthesis of qualitative evidence. Methods: Keyword searches were completed in SPORTDiscus, PubMed, Scopus, Web of Science, and Embase. Studies that offered perspectives relating to influences on the FMS of 2–6-year-old children in the family context via qualitative approaches, including visual methodologies that provided an important voice to children, were included. A thematic analysis was used to establish key themes. Results: The emergent themes included parent knowledge and beliefs, self-efficacy of parents to teach, and the home environment. Parents often undervalued FMS and lacked the self-efficacy to teach due to poor understanding, conflicting priorities, and multifaceted societal influences. Children preferred autonomous play and socialisation but were negatively influenced by technology and restrictive household rules. Conclusions: Greater knowledge exchange between stakeholders is necessary to empower parents and enhance FMS application at home. More community initiatives could facilitate greater access to outdoor spaces, facilities, and equipment, which may improve family engagement with FMS

A review of electrical metering accuracy standards in the context of dynamic power quality conditions of the grid

Numerous changes in electrical grid schemes, like the inclusion of renewable energy, the rise of non-linear loads and the emergence of electric vehicle charging, increases variable power quality conditions of the grid. In this dynamic scenario where energy could flow in both directions and the waveforms could be highly distorted, accuracy becomes a crucial factor for the correct measurement of electrical energy and power values. Errors in the assessment of these values have significant ramifications for revenue, billing and/or control. This non-ideal power quality scenario produces an error in electricity meters, that is not yet well known since there is no standardised procedure to calibrate meters under typical or emerging distorted waveform conditions. Current standards relevant for revenue energy meters like EN 50470-3:2006 allows measurements error up to ±2.5% while local regulations could be even more permissive. In order to establish an electricity fair trade market and meet expectations from consumers and utilities, electricity meters should arguably comply with higher accuracy standards. In this paper, the pertinence and possible impact of including tests under distorted waveform conditions, as well as new accuracy requirements on standards applicable to electricity meters for billing purposes will be discussed